[The role of guanidine groups of arginine residues of Na, K-ATPase and glutamate dehydrogenase in an interaction with cholesterol].

Cholesterol was studied in experiments in vitro for its effect on the activity of Na, K-ATPase of the synaptic brain membranes of rats and a crystalline preparation of glutamate dehydrogenase from the liver mitochondria of a bull. Cholesterol decreased the activity of the above enzymes. When blocking guanidine groups of arginine residues of Na, K-ATPase and glutamate dehydrogenase the inhibiting action of cholesterol was absent. The obtained data evidence for the possibility of a direct interaction of cholesterol with membrane enzymes as well as for the important significance of guanidine groups of arginine residues of proteins in the process.